A method and device for suppressing crosstalk between axes of a multi-axis silicon photonic gyroscope

Abstract

The present invention provides a method and device for suppressing crosstalk between axes of a multi-axis silicon photonic gyroscope. The crosstalk suppression method includes: connecting the optical path and circuit of the silicon photonic gyroscope, connecting the modulation electrode of the phase modulator of each channel to an independent signal generator, and connecting the detector output of each channel to an oscilloscope; controlling each signal generator to apply a square wave modulation signal to the modulation electrode; adjusting the frequency of the square wave modulation signal output by each signal generator so that the detector of the channel outputs a main signal waveform; collecting the crosstalk amplitude and rise delay of any other channel received in the sampling interval of each channel through an oscilloscope; determining the crosstalk characteristic parameters of any other channel received by each channel; replacing the signal generator with a signal detection output modulation signal; for each channel, judging the similarity between the output signal of the detector and the crosstalk characteristic parameters of any other channel, and then judging whether the output signal is a crosstalk signal; using borrow accumulation for the crosstalk signal, and using digital accumulation for the non-crosstalk signal. The crosstalk suppression method and device can effectively suppress the crosstalk noise between axes of a multi-axis silicon photonic gyroscope.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical gyroscopes, and in particular relates to a method and device for suppressing inter-axis crosstalk of a multi-axis silicon photonic gyroscope. Background Art

[0002] With the development of technology and the expansion of fields, interferometric fiber gyroscopes are gradually developing in the direction of miniaturization and low cost. The miniaturization and low cost development of traditional fiber gyroscopes face huge challenges. The main limiting factor is that the optical path of traditional multi-axis (dual-axis, tri-axis, etc.) fiber gyroscopes contains multiple discrete optical devices, up to more than ten melting points and pigtails that need to be processed, resulting in complex processes, large volumes, high costs, and low yields for medium and low precision tri-axis fiber gyroscopes. In recent years, silicon-based integrated optical chips have made breakthroughs and have been widely used in the field of communications, providing a new idea for the integration and miniaturization of fiber gyroscopes: replacing the discrete optical devices in traditional fiber gyroscopes with integrated optical chips, its volume, weight, cost, power consumption, etc. will be greatly reduced, so silicon photonic gyroscopes have become an important development direction for inertial devices.

[0003] At present, there are few reports on multi-axis silicon photonic gyroscopes. In addition to the great difficulty in designing and processing multi-axis optical chips, the inter-axis crosstalk of the multi-channel optical path at the detector end will also seriously restrict the accuracy of the gyroscope. Specifically, in the actual work of the X, Y, and Z axis PIN-FET receiving components on the multi-axis optical chip (taking three axes as an example), the absolute time constant is difficult to completely correspond to the crystal oscillator frequency division clock, resulting in the spike pulse of the X axis PIN-FET receiving component to produce voltage crosstalk on the straight section of the Y / Z axis PIN-FET receiving component. At the same time, the Y and Z axis PIN-FET receiving components will also produce voltage crosstalk on the X / Z axis and X / Y axis PIN-FET receiving components, resulting in the degradation of the accuracy of the multi-axis silicon photonic gyroscope. Depending on the degree of crosstalk, the accuracy of the gyroscope is usually degraded by 2-5 times. It is urgent to propose an effective noise suppression method and device for the inter-axis crosstalk problem of the multi-axis silicon photonic gyroscope to improve the performance of the multi-silicon photonic gyroscope. Summary of the invention

[0004] In view of the common inter-axis crosstalk problem of multi-axis silicon photonic gyroscopes in the prior art, the present invention provides a method and device for suppressing the inter-axis crosstalk of a multi-axis silicon photonic gyroscope.

[0005] The technical solution adopted by the present invention to solve the above technical problems is as follows:

[0006] As one aspect of the present invention, a method for suppressing crosstalk between axes of a multi-axis silicon photonic gyroscope is provided. The silicon photonic gyroscope includes at least two axes, each axis corresponds to a channel, and the method for suppressing crosstalk between axes includes the following steps:

[0007] S1, connect the optical path and circuit of the silicon photonic gyroscope, the modulation electrode of the phase modulator of each channel is connected to an independent signal generator, and the detector output of each channel is connected to an oscilloscope;

[0008] S2, controlling each signal generator to apply a square wave modulation signal to the modulation electrode;

[0009] S3, adjusting the frequency of the square wave modulation signal output by each signal generator so that the detector of the channel outputs the main signal waveform;

[0010] S4. Collect the crosstalk amplitude and rise delay of any other channel received in the sampling interval of each channel through an oscilloscope;

[0011] S5, determining the crosstalk characteristic parameters of any other channel received by each channel, wherein the crosstalk characteristic parameters include at least one group, and each group of crosstalk characteristic parameters includes a digital value of the crosstalk amplitude and the number of sampling points of the rise delay;

[0012] S6, replacing the signal generator with a signal detection output modulation signal;

[0013] S7, for each channel, determining the similarity between the output signal of the detector and the crosstalk characteristic parameter of any of its channels, and then determining whether the output signal is a crosstalk signal;

[0014] S8. If it is determined to be a crosstalk signal, the output data of the silicon photonic gyroscope adopts borrow accumulation, and the previous sampling data is borrowed as the accumulated data this time; if it is determined to be a non-crosstalk signal, the output data of the silicon photonic gyroscope adopts digital accumulation, and the current data is used as the accumulated data.

[0015] Furthermore, the calculation method of the digital value of the crosstalk amplitude is:

[0016]

[0017] Where r is the number of bits of the ADC used for crosstalk acquisition, V ADC To collect the full-scale digital output of the ADC, A digital value indicating the crosstalk amplitude of the m-axis from the n-axis, V 串扰_mn It represents the crosstalk amplitude of the m-axis affected by the n-axis, where m and n are the axes of the multi-axis silicon photonic gyroscope respectively, and m≠n;

[0018] The calculation method of the number of sampling points of the rise delay is:

[0019]

[0020] Among them, f ADC is the sampling rate of the analog-to-digital converter for crosstalk acquisition, Indicates the number of sampling points of the crosstalk rise delay of the m-axis due to the n-axis, T 串扰_mn It represents the crosstalk rise delay of the m-axis due to the n-axis, where m and n are respectively one axis of the multi-axis silicon photonic gyroscope, and m≠n.

[0021] Furthermore, in step S7, the specific method for determining the similarity between the output signal of the detector and the crosstalk characteristic parameter of any channel, and then determining whether the output signal is a crosstalk signal, is as follows:

[0022] If the amplitude of the output signal is within the range of plus or minus 20% of the digital value of the crosstalk amplitude of a certain set of crosstalk characteristic parameters, and the rise delay of the output signal is within the range of plus or minus 20% of the number of sampling points of the rise delay of the set of crosstalk characteristic parameters, then the signal is determined to be a crosstalk signal, otherwise it is a non-crosstalk signal.

[0023] Furthermore, in step S7, if the silicon photonic gyroscope is three-axis integrated, the channel to be tested receives two groups of crosstalk signals from the other two channels, and the two groups of crosstalk signals are judged for similarity.

[0024] Furthermore, in step S2, the amplitude of the square wave modulation signal is the half-wave voltage of the channel phase modulator, and the initial frequency of the square wave modulation signal is the intrinsic frequency of the channel optical fiber loop.

[0025] Furthermore, step 1 also includes powering on the silicon photonic gyroscope and recording the photovoltage of each detector in a non-modulated state; in step S3, the main signal waveform is a spike pulse signal, and the maximum value of its spike voltage is at least more than half of the photovoltage of the channel detector in a non-modulated state.

[0026] As another aspect of the present invention, a device for suppressing inter-axis crosstalk of a multi-axis silicon photonic gyroscope is provided. The silicon photonic gyroscope includes at least two axes. The device for suppressing inter-axis crosstalk includes a digital signal processing circuit. The digital signal processing circuit is arranged on the signal detection circuit of the silicon photonic gyroscope, and includes a digital filtering module, an inter-axis crosstalk suppression module, and a signal demodulation module. The digital filtering module is used to receive output signals of detectors of each axis for filtering and noise suppression. The inter-axis crosstalk suppression module is used to identify the signal output by the digital filtering module to determine whether it is a crosstalk signal. The signal demodulation module is used to demodulate the signal and output the gyroscope data of each axis.

[0027] Furthermore, the inter-axis crosstalk suppression module includes a high-frequency clock module, a crosstalk identification module, and a crosstalk processing module; the high-frequency clock module is used to generate a clock signal for crosstalk sampling; the crosstalk identification module is used to establish the crosstalk characteristic parameters of the axis to be measured, and judge whether the signal of the axis to be measured is a crosstalk signal or a non-crosstalk signal according to the similarity between the main signal of the axis to be measured and the crosstalk characteristic parameters, and output a crosstalk processing command word; the crosstalk processing module is used to perform signal processing according to the crosstalk processing command word, perform borrow accumulation processing on the crosstalk signal, and perform digital accumulation processing on the non-crosstalk signal.

[0028] Furthermore, the intrinsic frequency of the high-frequency clock module is in the range of 10 MHz to 100 MHz.

[0029] Furthermore, the digital signal processing circuit also includes a PI control module and a modulation signal module. The PI control module is used to control and process the demodulated signal, add the step wave output by the modulation signal module, and act on the modulation electrodes of the X-axis, Y-axis and Z-axis channels respectively.

[0030] The beneficial effects of the present invention compared with the prior art are as follows:

[0031] The present invention proposes a method and device for suppressing inter-axis crosstalk of a multi-axis silicon photonic gyroscope. By introducing an inter-axis crosstalk detection module into a traditional signal processing circuit, the amplitude and time information of the signal to be measured are analyzed and separated from the traditional carrier speed signal. Once inter-axis crosstalk is detected, an avoidance sampling algorithm is used to suppress it without losing the sampling rate and ensuring the gyroscope signal-to-noise ratio. The crosstalk suppression method and device can effectively suppress inter-axis crosstalk noise, and have the technical characteristics of being accurate, fast, and effective.

[0032] The crosstalk suppression method of the present invention is simple to implement, convenient for engineering application, and suitable for the production and manufacture of batch silicon photonic gyroscopes. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 A schematic diagram of the structure of a three-axis silicon photonic gyroscope provided in a specific embodiment of the present invention;

[0035] Figure 2 Schematic diagram of the crosstalk effect between axes of a multi-axis silicon photonic gyroscope;

[0036] Figure 3 A schematic diagram of the structure of a digital signal processing circuit provided by a specific embodiment of the present invention;

[0037] Figure 4 A schematic diagram of the structure of an inter-axis crosstalk suppression module provided in a specific embodiment of the present invention;

[0038] Figure 5 A schematic diagram of the connection relationship between the Y-waveguide modulation electrode and the signal generator, the detector and the oscilloscope provided in a specific embodiment of the present invention;

[0039] Figure 6 A schematic diagram of crosstalk amplitude and rise time delay provided for a specific embodiment of the present invention. DETAILED DESCRIPTION

[0040] Specific embodiments of the present invention are described in detail below. In the following description, for the purpose of explanation and not limitation, specific details are set forth to help fully understand the present invention. However, it will be apparent to those skilled in the art that the present invention may also be practiced in other embodiments that depart from these specific details.

[0041] It should be noted that in order to avoid obscuring the present invention due to unnecessary details, only the device structure and / or processing steps closely related to the scheme of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0042] As a specific embodiment of the present invention, a method for suppressing crosstalk between axes of a multi-axis silicon photonic gyroscope is provided. The silicon photonic gyroscope includes at least two axes, each axis corresponds to a channel, and at least a detector of each channel is integrated on the chip of the silicon photonic gyroscope. The method for suppressing crosstalk between axes includes the following steps:

[0043] S1, connect the optical path and circuit of the silicon photonic gyroscope, the modulation electrode of the phase modulator of each channel is connected to an independent signal generator, and the detector output of each channel is connected to an oscilloscope;

[0044] S2, controlling each signal generator to apply a square wave modulation signal to the modulation electrode;

[0045] S3, adjusting the frequency of the square wave modulation signal output by each signal generator so that the detector of the channel outputs the main signal waveform;

[0046] S4. Collect the crosstalk amplitude and rise delay of any other channel received in the sampling interval of each channel through an oscilloscope;

[0047] S5, determining the crosstalk characteristic parameters of any other channel received by each channel, wherein the crosstalk characteristic parameters include at least one group, and each group of crosstalk characteristic parameters includes a digital value of the crosstalk amplitude and the number of sampling points of the rise delay;

[0048] S6, replacing the signal generator with a signal detection output modulation signal;

[0049] S7, for each channel, determining the similarity between the output signal of the detector and the crosstalk characteristic parameter of any of its channels, and then determining whether the output signal is a crosstalk signal;

[0050] S8. If it is determined to be a crosstalk signal, the output data of the silicon photonic gyroscope adopts borrow accumulation, and the previous sampling data is borrowed as the accumulated data this time; if it is determined to be a non-crosstalk signal, the output data of the silicon photonic gyroscope adopts digital accumulation, and the current data is used as the accumulated data.

[0051] The present invention detects the inter-axis crosstalk signal of the multi-axis silicon photonic gyroscope, constructs the crosstalk characteristic parameters received by each measured axis from other channels, and determines whether the measured signal is a crosstalk signal by analyzing the similarity between the amplitude and time information of the measured signal and the characteristic parameters of the crosstalk signal. The crosstalk signal is circumvented to achieve inter-axis crosstalk suppression.

[0052] The multi-axis silicon photonic gyroscope inter-axis crosstalk suppression method provided by the present invention is suitable for crosstalk suppression processing of two-axis, three-axis and other silicon photonic integrated chips. For multiple channels, the crosstalk characteristic parameters received by each measuring axis from other channels are independently determined, and the crosstalk of different channels is judged separately to ensure the effectiveness of detection.

[0053] As another specific implementation of the present invention, taking a three-axis silicon photonic gyroscope structure as an example, a method and device for suppressing inter-axis crosstalk of a multi-axis silicon photonic gyroscope are provided.

[0054] The structure of the three-axis silicon photonic gyroscope is as follows: Figure 1As shown, it mainly includes a three-axis silicon photonic chip, a drive control circuit, a signal detection circuit and an X / Y / Z axis header, and the header is composed of an optical fiber ring and a Y waveguide. The basic principle of the three-axis silicon photonic gyroscope includes: the three-axis optical signals emitted by the three-axis silicon photonic chip enter the X / Y / Z axis header respectively. When rotation occurs, the interference light intensity signal caused by the rotation is output to the drive control circuit through the three-channel detector of the three-axis silicon photonic chip, and enters the signal detection circuit through a flexible connection line for signal processing. As an improvement of the present invention, the signal processing link of the signal detection circuit includes the inter-axis crosstalk suppression algorithm and the corresponding inter-axis crosstalk suppression module proposed by the present invention. From the functional aspect, the three-axis silicon photonic chip mainly realizes the optical signal receiving and sending and coupling and splitting functions of the three-axis silicon photonic gyroscope; the drive control circuit is connected according to the pin definition of the three-axis silicon photonic chip to realize the constant temperature and constant current control function; the X / Y / Z axis header mainly realizes the angular velocity sensitivity and signal modulation functions of the three axes; the signal detection circuit realizes the functions of gyroscope signal filtering, modulation and demodulation, inter-axis crosstalk suppression and data communication.

[0055] The influence mechanism of inter-axis crosstalk on gyroscope performance is as follows: Figure 2 As shown: detectors 1, 2, and 3 are integrated on a single silicon-based optical chip. Due to the close physical spacing, the main signal of the X-axis will be serially transmitted to the straight section of the Y-axis (i.e., the sampling interval of the Y-axis) after the closed loop is successful. Similarly, the main signal of the Y-axis will also affect the straight section of the X-axis (i.e., the sampling interval of the X-axis). Similarly, the main signal of the Z-axis will also affect the straight sections of the X-axis and Y-axis, thereby causing a significant degradation of the gyroscope accuracy.

[0056] As a specific implementation of the present invention, in order to suppress the inter-axis crosstalk of the multi-axis silicon photonic gyroscope, the present invention sets an inter-axis crosstalk suppression algorithm and a corresponding inter-axis crosstalk suppression module in the signal processing link of the signal detection circuit. The signal detection circuit structure is as follows: Figure 3 As shown, the signal detection circuit includes a digital signal processing circuit, which includes a digital filtering module, an inter-axis crosstalk suppression module, and a signal demodulation module. The digital filtering module is used to receive the output signals of the X-axis, Y-axis and Z-axis detectors for filtering and noise suppression. The inter-axis crosstalk suppression module is used to identify the signal output by the digital filtering module and determine whether it is a crosstalk signal. The signal demodulation module is used to demodulate the signal and output the gyro data of the X-axis, Y-axis and Z-axis. The working process of the signal detection circuit is as follows: the X-axis, Y-axis and Z-axis inputs are respectively derived from the three-way detector output on the three-axis silicon photonic chip. The input signal is subjected to white noise suppression by the digital filtering module, and then enters the inter-axis crosstalk suppression module for inter-axis crosstalk identification. After identifying as inter-axis crosstalk, the crosstalk avoidance algorithm is started, otherwise the signal is demodulated normally, and the X-axis, Y-axis and Z-axis gyro data are output respectively.

[0057] In addition, since this implementation adopts a digital closed-loop solution, it is also necessary to integrate a PI control module in the digital signal processing circuit according to the demodulated signal, and add it to the step wave generated by the modulation signal module (through a digital adder) and act on the modulation electrodes of the X-axis, Y-axis and Z-axis Y waveguide respectively to realize the digital closed loop of the gyroscope, thereby significantly improving the dynamic range of the three-axis silicon photonic gyroscope and ensuring that it has good scale factor nonlinearity under a large dynamic range.

[0058] As a specific implementation of the present invention, the main structure of the inter-axis crosstalk suppression module is as follows: Figure 4 As shown, it includes a high-frequency clock module, a crosstalk identification module and a crosstalk processing module. Among them, the high-frequency clock module is used to generate a clock signal for the crosstalk sampling analog-to-digital converter (ADC). Since the loop length is mostly concentrated in 100-1000 meters, according to the intrinsic frequency calculation formula c / 2nL i (where c is the speed of light in a vacuum, n is the refractive index of the optical fiber, L j is the length of a certain optical fiber loop, i=1,2,3, i represents a channel), the intrinsic frequency of the high-frequency clock module is mostly between 100kHz and 1MHz. In order to achieve distortion-free sampling of the crosstalk signal, the ADC sampling rate is mostly controlled to 100 times of it, and the intrinsic frequency of the high-frequency clock module is in the range of 10MHz to 100MHz. The crosstalk identification module is mainly used to establish the crosstalk characteristic parameters of the axis to be measured, and to judge the amplitude and rise time delay according to the main signal and crosstalk characteristic parameters of the axis to be measured, and to judge whether the axis signal to be measured is a crosstalk signal or a non-crosstalk signal, and output a crosstalk processing command word. Specifically, the crosstalk identification module also includes an amplitude comparison submodule and a delay comparison submodule, which are respectively used to judge the relationship between the amplitude, rise time delay and crosstalk characteristic parameters of the main signal of the axis to be measured. The crosstalk processing module is mainly used to perform signal processing according to the obtained crosstalk processing command word, perform borrow accumulation processing on the crosstalk signal, and perform digital accumulation processing on the non-crosstalk signal, so as to ensure the effective suppression of the crosstalk signal between axes under the premise of ensuring a certain signal-to-noise ratio.

[0059] As another specific embodiment of the present invention, in order to suppress the inter-axis crosstalk of the multi-axis silicon photonic gyroscope, the present invention sets an inter-axis crosstalk suppression algorithm and a corresponding inter-axis crosstalk suppression module in the signal processing link of the signal detection circuit. The main processing flow of the inter-axis crosstalk suppression algorithm is as follows:

[0060] S1: Connect the optical path and circuit of the three-axis silicon photonic gyroscope. The modulation electrodes of the three Y waveguides (the phase modulator in this embodiment is an integrated Y waveguide) are respectively connected to three independent signal generators. The signal generator is used to simulate the modulated square wave. The three detector outputs of the three-axis silicon photonic chip are all connected to the oscilloscope. Figure 5The signal detection circuit and the drive control circuit are powered on by an external power supply, and the output voltages of the three detectors are recorded (the output voltage is the light-on voltage of the detector in the non-modulated state), which are respectively recorded as V pp_1 、V pp_2 and V pp_3 .

[0061] S2: Apply three independent square wave modulation signals to the three Y waveguides of the three-axis silicon photonic gyroscope. The amplitude of the square wave modulation signal is initially set to V π_1 、V π_2 and V π_3 , where V π_1 、V π_2 and V π_3 are the half-wave voltages of the three Y-waveguides, which are given in the Y-waveguide data sheet; the initial frequency of the square wave modulation signal is first set to the eigenfrequency of the three fiber loops according to the different loop lengths, namely c / 2nL1, c / 2nL2 and c / 2nL3, where c is the speed of light in vacuum, n is the refractive index of the fiber, L1, L2, L3 are the lengths of the three fiber loops, n and L i (i=1, 2, 3, corresponding to three channels) Affected by the curvature of the optical fiber and the ambient temperature, the calculation result of the eigenfrequency of the optical fiber loop is only a theoretical value. Using this initial value can facilitate the rapid adjustment of the main signal waveform.

[0062] S3: Adjust the frequency of the square wave modulation signals output by the three signal generators so that the outputs of the three detectors are Figure 2 The peak pulse signal in the pulse signal has a peak voltage of at least V pp_i / 2, regarded as the main signal waveform.

[0063] S4: Read the inter-axis interference size of the X-axis, Y-axis and Z-axis sampling areas on the oscilloscope respectively, such as Figure 6 As shown, record the crosstalk amplitude V received by each axis 串扰_XY 、V 串扰_XZ 、V 串扰_YX 、V 串扰_YZ 、V 串扰_ZX 、V 串扰_ZY and rise time delay T crosstalk _XY , T crosstalk _XZ 、T 串扰_YX 、T 串扰_YZ 、T 串扰_ZX 、T 串扰_ZY ; Among them, V 串扰_mn Indicates the crosstalk amplitude of the m-axis from the n-axis, T 串扰_mn It indicates the crosstalk rise delay of the m-axis due to the n-axis, m and n are respectively one axis of the multi-axis silicon photonic gyroscope, and m≠n. In this embodiment, m and n are one of the X, Y, and Z axes.

[0064] For a three-axis silicon photonic gyroscope, one of the axes is used as the main axis to be measured. The main axis to be measured will be affected by the inter-axis interference signal generated by the other two axes. The inter-axis interference of these two axes needs to be determined and processed separately.

[0065] S5: In the crosstalk identification module, the digital value of the crosstalk amplitude is established according to formula (1). The number of sampling points of the rise delay Determined by the high-frequency clock sampling rate, it is established according to formula (2), and is the crosstalk characteristic parameter.

[0066] Digital value of crosstalk amplitude

[0067]

[0068] Where r is the number of bits of the ADC (analog-to-digital converter) used for crosstalk acquisition, V ADC To collect the full-scale digital output of the ADC, A digital value indicating the crosstalk amplitude of the m-axis from the n-axis, V 串扰_mn It represents the crosstalk amplitude of the m-axis affected by the n-axis, where m and n are respectively one axis of the multi-axis silicon photonic gyroscope, and m≠n.

[0069] Number of sampling points for rise delay

[0070]

[0071] Among them, f ADC is the sampling rate of the ADC used for crosstalk acquisition, Indicates the number of sampling points of the crosstalk rise delay of the m-axis due to the n-axis, T 串扰_mn It represents the crosstalk rise delay of the m-axis due to the n-axis, where m and n are respectively one axis of the multi-axis silicon photonic gyroscope, and m≠n.

[0072] By judging the similarity between the output signal of the detector and the crosstalk characteristic parameters of any other channel, it is determined whether the output signal is a crosstalk signal. In this embodiment, the similarity between the output signal and the crosstalk characteristic parameters of any other channel is judged by the following method:

[0073] When the amplitude of the signal to be measured is near the digital value of the crosstalk amplitude of a certain set of crosstalk characteristic parameters (±20%), and the delay is also near the number of sampling points of the rise delay of the set of crosstalk characteristic parameters (±20%), the signal can be considered to be a crosstalk signal.

[0074] S6: Remove the signal generator and replace it with a signal detection circuit to output the modulated signal.

[0075] S7: Determine the crosstalk amplitude. When the three detector signals are input, the signals are first sampled by ADC. The collected amplitude data enters the amplitude comparison module. If Within the range, the amplitude can be considered to meet the inter-axis crosstalk characteristics;

[0076] S8: Perform crosstalk delay judgment, and input the delay data collected by ADC into the time comparison module. If Within the range, it can be considered that the delay meets the characteristics of inter-axis crosstalk;

[0077] S9: The crosstalk identification module determines whether it is a crosstalk signal based on the determination of steps S7 and S8. The rule is: if the amplitude and delay both meet the characteristics of inter-axis crosstalk, it can be considered a crosstalk signal. On this basis, a processing command is generated, "0" represents a non-crosstalk signal, and "1" represents an inter-axis crosstalk signal;

[0078] S10: If it is determined that this is an inter-axis crosstalk signal, the crosstalk processing module uses borrow accumulation, that is, borrowing the previous sampling data (k-1) as the data to be accumulated this time (k times). At this time, the accumulated data D ks As shown in formula (3):

[0079] D ks =D1+D2…+D k-1 +D k-1 +D k+1 …+D K (3)

[0080] Among them, k is the number of sampling times, K is the maximum number of sampling times for a single sampling, and the value of N satisfies the following relationship:

[0081] (kL i f ADC ) / 2c≤N≤(kL i f ADC ) / c (4)

[0082] If it is determined that this is a normal gyro signal, the crosstalk processing module uses digital accumulation, that is, the current data is normally used as the data to be accumulated. At this time, the accumulated data D ks As shown in formula (5):

[0083] D ks =D1+D2…+D k-1 +D k +D k+1 …+D K (5)

[0084] From formulas (3) and (5), it can be seen that by adopting the inter-axis crosstalk suppression algorithm, the signal-to-noise ratio of the gyroscope can be guaranteed without losing the sampling rate, and it has the technical characteristics of accuracy, speed and significant effect.

[0085] In addition, the above steps are only for the description of the inter-axis crosstalk suppression algorithm, not a complete closed-loop control process. The PI control and modulation signal generation in the closed-loop control process adopt the traditional fiber optic gyroscope digital processing algorithm.

[0086] Features described and / or illustrated above for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or used in place of features in other embodiments.

[0087] It should be emphasized that the term "include / comprises" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps, components or combinations thereof.

[0088] The many features and advantages of these embodiments are apparent from this detailed description, and thus the appended claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not intended that the embodiments of the invention be limited to the exact construction and operation illustrated and described, but rather all suitable modifications and equivalents falling within the scope thereof are intended to be covered.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0090] Parts of the present invention that are not described in detail are well known to those skilled in the art.

Claims

1. A method for suppressing crosstalk between axes of a multi-axis silicon photonic gyroscope, characterized in that: The silicon photonic gyroscope comprises at least two axes, each axis corresponds to a channel, and the inter-axis crosstalk suppression method comprises the following steps: S1, connect the optical path and circuit of the silicon photonic gyroscope, the modulation electrode of the phase modulator of each channel is connected to an independent signal generator, and the detector output of each channel is connected to an oscilloscope; S2, controlling each signal generator to apply a square wave modulation signal to the modulation electrode; S3, adjusting the frequency of the square wave modulation signal output by each signal generator so that the detector of the channel outputs the main signal waveform; The main signal waveform is a spike pulse signal, and the maximum value of its spike voltage is at least half of the photoelectric voltage of the channel detector in the non-modulation state; S4. Collect the crosstalk amplitude and rise delay of any other channel received in the sampling interval of each channel through an oscilloscope; S5, determining the crosstalk characteristic parameters of any other channel received by each channel, wherein the crosstalk characteristic parameters include at least one group, and each group of crosstalk characteristic parameters includes a digital value of the crosstalk amplitude and the number of sampling points of the rise delay; The calculation method of the digital quantity of the crosstalk amplitude is: Where r is the number of bits of the ADC used for crosstalk acquisition, V ADC To collect the full-scale digital output of the ADC, A digital value indicating the crosstalk amplitude of the m-axis from the n-axis, V 串扰_mn It represents the crosstalk amplitude of the m-axis affected by the n-axis, where m and n are the axes of the multi-axis silicon photonic gyroscope respectively, and m≠n; The calculation method of the number of sampling points of the rise delay is: Among them, f ADC is the sampling rate of the analog-to-digital converter for crosstalk acquisition, Indicates the number of sampling points of the crosstalk rise delay of the m-axis due to the n-axis, T 串扰_mn It indicates the crosstalk rise delay of the m-axis due to the n-axis, where m and n are the axes of the multi-axis silicon photonic gyroscope, and m≠n; S6, replacing the signal generator with a signal detection output modulation signal; S7, for each channel, determining the similarity between the output signal of the detector and the crosstalk characteristic parameter of any of its channels, and then determining whether the output signal is a crosstalk signal; S8. If it is determined to be a crosstalk signal, the output data of the silicon photonic gyroscope adopts borrow accumulation, and the previous sampling data is borrowed as the accumulated data this time; if it is determined to be a non-crosstalk signal, the output data of the silicon photonic gyroscope adopts digital accumulation, and the current data is used as the accumulated data.

2. The method for suppressing inter-axis crosstalk of a multi-axis silicon photonic gyroscope according to claim 1, characterized in that: The specific method for determining the similarity between the output signal of the detector and the crosstalk characteristic parameter of any channel in step S7, and then determining whether the output signal is a crosstalk signal, is as follows: If the amplitude of the output signal is within the range of plus or minus 20% of the digital value of the crosstalk amplitude of a certain set of crosstalk characteristic parameters, and the rise delay of the output signal is within the range of plus or minus 20% of the number of sampling points of the rise delay of the set of crosstalk characteristic parameters, then the signal is determined to be a crosstalk signal, otherwise it is a non-crosstalk signal.

3. The method for suppressing inter-axis crosstalk of a multi-axis silicon photonic gyroscope according to claim 2, characterized in that: In step S7, if the silicon photonic gyroscope is three-axis integrated, the channel to be tested receives two groups of crosstalk signals from the other two channels, and the two groups of crosstalk signals are judged for similarity.

4. The method for suppressing inter-axis crosstalk of a multi-axis silicon photonic gyroscope according to claim 1, characterized in that: In step S2, the amplitude of the square wave modulation signal is the half-wave voltage of the channel phase modulator, and the initial frequency of the square wave modulation signal is the intrinsic frequency of the channel optical fiber loop.

5. The method for suppressing inter-axis crosstalk of a multi-axis silicon photonic gyroscope according to claim 1, characterized in that: The step S1 also includes powering on the silicon photonic gyroscope and recording the photovoltage of each detector in a non-modulated state.

6. A device for suppressing crosstalk between axes of a multi-axis silicon photonic gyroscope, characterized in that: The inter-axis crosstalk suppression method according to any one of claims 1 to 5 is adopted, and the inter-axis crosstalk suppression device includes a digital signal processing circuit, and the digital signal processing circuit is arranged on the signal detection circuit of the silicon photonic gyroscope, including a digital filtering module, an inter-axis crosstalk suppression module, and a signal demodulation module. The digital filtering module is used to receive the output signal of each axis detector for filtering and noise suppression processing, the inter-axis crosstalk suppression module is used to identify the signal output by the digital filtering module to determine whether it is a crosstalk signal, and the signal demodulation module is used to demodulate the signal and output the gyroscope data of each axis.

7. The device for suppressing inter-axis crosstalk of a multi-axis silicon photonic gyroscope according to claim 6, characterized in that: The inter-axis crosstalk suppression module includes a high-frequency clock module, a crosstalk identification module, and a crosstalk processing module; the high-frequency clock module is used to generate a clock signal for crosstalk sampling; the crosstalk identification module is used to determine the crosstalk characteristic parameters of the axis to be measured, and judge whether the axis signal to be measured is a crosstalk signal or a non-crosstalk signal according to the similarity between the axis signal to be measured and the crosstalk characteristic parameters, and output a crosstalk processing command word; the crosstalk processing module is used to perform signal processing according to the crosstalk processing command word, perform borrow accumulation processing on the crosstalk signal, and perform digital accumulation processing on the non-crosstalk signal.

8. The device for suppressing inter-axis crosstalk of a multi-axis silicon photonic gyroscope according to claim 7, characterized in that: The intrinsic frequency of the high-frequency clock module is in the range of 10 MHz to 100 MHz.

9. The device for suppressing inter-axis crosstalk of a multi-axis silicon photonic gyroscope according to claim 6, characterized in that: The digital signal processing circuit also includes a PI control module and a modulation signal module. The PI control module is used to control and process the demodulated signal, add the step wave output by the modulation signal module, and act on the modulation electrodes of the X-axis, Y-axis and Z-axis channels respectively.

Images